1. Background of the Invention
The present invention relates to a system for an air conditioning unit utilizing a refrigeration cycle capable of obtaining either a cooling, or heating operation and a dehumidifying operation. The present invention is, in particular, suitable for an air conditioning system for an electrically operated automobile.
2. Description of the Related Art
Known in a related art is an air conditioning system where a refrigeration cycle is utilized for switching between a cooling or heating operation and a dehumidifying operation. See Japanese Patent Application No. 3-319417 corresponding U.S. Pat. application Ser. No. 07/873,430 now U.S. Pat No. 5,299,431 filed on Apr. 24, 1992 by the assignee of this patent application.
In the related art, the downstream heat exchanger acts as a condenser for imparting heat from the refrigerant to the air in a duct having outlets opened to desired locations of the cabin upon using both the heating and dehumidifying mode. The upstream heat exchanger is closed to the recirculated cycle upon using the heating mode. Upon use of the dehumidifying mode, the upstream heat exchanger is located in the refrigerating closed circuit for acting as an evaporator for removing heat from the air in the duct.
An outside heat exchanger is also located in the refrigerant closed circuit. In the prior art, the outside fan only acts as a passageway of the refrigerant upon use of the dehumidifying mode.
During the dehumidifying operation a large amount of refrigerant is required for the refrigerant cycle, thereby exhausting the liquid refrigerant in the accumulator. In order to prevent the same from occurring, an accumulator with a large volume is required.